Improved guard attachment for locks



UNITED STATES PATENT OEEICE.

ILLIAM MILLER, OF BOSTON, MASSACHUSETTS.

IMPROVED GUARD ATTACHMENT FORLOCKS.

Specification forming part of Letters Patent No. 40,1!5, dated September29, 1863.

.T0 all whom t may concern.'

Be it known that I, WILLIAM MILLER, of Boston, in the county of Suolkand State of Massachusetts, have invented a new and Improved GuardAttachment tor Locks; and I do hereby declare that the following is afull, clear, and exact description of the same, reference being had tothe accompanying drawings, making a part of this specification, inwhich- Figure 1 is a front or face view ot' a portion of a door having amortise lock titted in it with my invention applied to it; Fig. 2, a section ofthe same, taken in the line a a; Fig. 3, a detached perspectiveview of my invention.

Similar letters of reference indicate corresponding parts in the severaltigures.

The object ot' this invention is to obtain a simple, eliicient, andcheap device which may be readily applied to a lock and to the keythereof in such a manner as to prevent the turning ofthe key at theouter side ot' the door, an expedient frequently resorted to by burglarstopen doors when locked, and the key left in the inner side ofthe lock.

llhe invention consists in the employment or use ot'a metal plate bentso as to form a t-lasp, which may be fitted over the bow of the key, soas to be secured thereto and have one end fitted in the key-hole,substantially as hereinalter fully shown and described, whereby thedesired end is attained.

To enable those skilled in the art to fully understand and constructInyinvention, I wil'. proceed to describe it.

YA represents a portion of a door containing a tnortise-lock, B, of the.usual or any proper construction. O is the key, represented as being inthe lock, and provided with the usual bow a, by which it Ina-y bereadily turned by the hand.

D is -a clasp, formed of a flat metal plate bent in V form, or in a formapproximating thereto and having one of its legs or parts, b, ratherlonger tha-n the other one. c. The larv gest leg, or part b of the claspterminates in a loop, d, which is shown clearly in Figs. 2 and 3, theloop being` considerably narrower than the plate, so that the former mayreadily enter the key-hole E of the lock. The end ofthe short part O ofthe clasp terminates in a fork or claw, e, shown clearly in Fig. 3, anda loop, f, is also attached to the short end of the clasp, said loopserving as a handle to aid in lifting or raising the part O whennecessary.

The device is applied to the lock and key as follows: The clasp is ttedon the bow a of the key, the loop d entering the key-hole E, and theclaw e fitting over the arbor or shank g of the key at the junction ofthe latter with the bow. The clasp has suttcient spring or elasticity initself to keep the claw c in the arbor or shank g of the key.

The clasp D is sufficiently broad to cover the greater portion ot' thebow a of the key, and it will be seen that when the olas is applied tothe key and lock as described the key cannot be turned at the outer sideof the door, as the clasp encompasses the bow a, and the former isprevented from turning on account of the loop d fitting in thekey-holeE. The claw c, in consequence of fitting on the shank or arbor g of thekey in front ofthe bow a, together with the spring or elasticityoftheclasp, prevents the latter from being casually detached from the bowand the loop d from slipping out from the key-hole E. The clasp may bedetached from the bow tof the key wh'en necessary by raising the part cby means of the loop j', so that the claw may be free from the arbor onshank g of the key.

The clasp D is sufficiently broad to cover the greater portion of thebow a of the key, and it will be seen that when the clasp is applied tothe key and lock as described the key cannot be turned at the outer sideot' thel door, as the clasp encompasses the bow a and the former isprevented from turning von account ot' the loop d iitting in thekey-hole E. The

arbor g of the key infront ot the bow a, together with the spring orelasticity ot the clasp, prevents the. latter from being' casuallydetached from the bow and the loop d from slipping out from the key-holeE. The clasp may be detached from the bow a of the key when'necessary byraising the part o by means ot the loop j', so that the claw e may befree from the arbor o'n sha-nk g ofthe key.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

lhe clasp D, constructed substantially as shown, so as to be capable ofbeing fitted on (See Fig. 2.) l the bow a of the key O with one end inthe i key-hole E, as and for the purpose set forth.

WM. MILLER. Witnesses:

M. M. LIvINGsToN, J W. OooMBs.

claw, in consequence ot Iitting on the shank or

